Spinning Wing Airliner (Aug, 1950)

More wing lift and less drag are the major aims of aviation’s researchers. Maybe the Magnus Wing will supply the answers.

ENGLAND’S aeronautical scientists may have a surprise in store for the rest of the flying world. Some years ago a prominent investigator, Anton Flettner, formulated the Magnus Effectâ€”the strange behavior of a drum spinning in an airflow. Today with modern materials, equipment and wind tunnels, interest is once more directed toward this strange phenomenon.
The lift of an airplane wing is caused by the fact that the air passing over the top of a wing travels faster than that passing over the bottom. A law of science says that the faster air travels, the more its pressure is reduced. This difference in air pressure between the top and bottom of the wing results in lift. The addition of a rotating drum speeds up the air over the wing and slows up the air under the wing still more, resulting in still greater pressure difference and hence, greater lift. Early tests show an increase of 100 to 200 per cent.

Here is how one of tomorrow’s airliners may appear should further experiments prove the idea practical. The ship is powered by a conventional gas-turbine jet engine, while the drums are revolved by a separate piston engine. Small wings, heavy loads and quick take-offs would be its great advantages.

> Many flying machines incorporate this idea by generating lift with a
> rotating cylinder at the front of a wing that allows flight at lower
> horizontal speeds. [1] (Flettner rotor plane)
>
> A remote controlled prototype was featured on the DIY network show,
> “Radio-Control Hobbies” that used the Magnus effect as the primary lift
> and thrust mechanism. It consisted of a fan-like rotator generating the
> Magnus effect which allowed it to lift off after traveling only a few feet
> forward.
>
> A series of prototypes were built of a design called FanWing. Wind-tunnel
> tests were conducted in 1998 by Pat Peebles at the University of Rome.
>
> A patent was filed by Fred Ferguson in the 1980’s for an airship which
> used the Magnus effect as its primary lift and propulsion.
>
> The Rotor and UFO kites use the Magnus effect for lift.

JMyint says: May 17, 200811:33 am

“The lift of an airplane wing is caused by the fact that the air passing over the top of a wing travels faster than that passing over the bottom. A law of science says that the faster air travels, the more its pressure is reduced. This difference in air pressure between the top and bottom of the wing results in lift. The addition of a rotating drum speeds up the air over the wing and slows up the air under the wing still more, resulting in still greater pressure difference and hence, greater lift. Early tests show an increase of 100 to 200 per cent.”

This is known as the Bernoulli’s principle and it is not why planes fly. If’n it were the case airplanes could not fly upside down.

The Magnus effect is one of many various quirks in aerodynamics that is just not scalable. Yeah a bumble bee can fly but you are not going to see a man sized bumble bee type flying machine.

Blurgle says: May 18, 200812:06 am

JMyint, most aircraft can’t fly upside down for more than a second or so. If lift doesn’t allow aircraft to fly, pray tell what does?

Baron Waste says: May 18, 20086:17 am

Blurgle: I would surmise he’s thinking of jet aircraft, which travel so fast that they ‘plane’ through the air like water-skies on the water. Their wings are more lens-shaped in cross section, sometimes diamond-shaped: Air pressure and lift are indeed irrelevant at 400 miles per hour.

It’s angle of attack that provides lift. The reason most planes can only fly upside down for a short period is not because of lift but because of mechanical limitations. Fuel tanks and pumps designed with a specific up and down, engine mounts designed with gravity in mind are what limit a planes ability to fly inverted.

Early in the days of aviation the Bernoulli principle seemed to be what was holding planes up but when exotic aircaft types with different wing shape were investigated it was found that something else was providing lift.

It is angle of attack that provides lift. Most airplanes can only fly inverted for a seconds because of mechanical limitations not aerodynamic ones. Fuel tanks and fuel pumps that are designedwith a specific up and down in mind, engine mounts designed for gravity in one direction. The Piper Cub had the fuel tank above the pilot with gravity feed.

Originally it was thought the Bernoulli principle was what gave airplanes lift until the problem of the upside down airplane was considered. Then the investigation into new wing shapes also distanced Bernoulli’s as the primary source of lift.

The other thing I find odd about this, is the assumed need for a second engine to turn the cylinder! The main engine would provide plenty of power – it powers all the onboard systems of modern airliners, including the hydraulics – which can get sticky if the engines flame out in midair, as happened once from a faulty fuel gauge. (Interestingly, in that case a little propeller-driven generator popped out of the hull automatically and provided power to the hydraulicsâ€¦ which only got sticky when the pilot was landing, and shed his airspeed, and his controls started freezing upâ€¦)

Pittance says: May 25, 20087:19 am

Newton’s second law provides lift, just like with all inertial forces.

Aircraft create lift (upwards force) because they push down on the air and so change its momentum (combination of mass and velocity). If they pushed up on the air they’d create a downforce – physics doesn’t care about the direction…

Newton’s second law says force is equal to rate of change of momentum so when I change the momentum of a bit of air I get a force. (In fact this force isn’t just lift it’s also a bit of drag but that’s not important right now…)

There is, however _also_ a change of pressure over the wing – these two effects aren’t separate they’re two sides of the same coin; pressure is just force distributed over an area. Newton’s third law which says that (to paraphrase) “if I push on this air it pushes back on me with equal strength in the opposite direction”. So if an aircraft pushes down on the air, the air must push up on it, hence lift. Pressures are the way that these forces are transferred to the structure of the aircraft.

There’s no magic, physics doesn’t somehow ignore aircraft.

The air _does_ flow faster over the top of a wing because of two reasons, incidence (angle to the airflow) and the shape of the wing. This is why an aircraft goes nose-up to increase lift and why it can use flaps and other control surfaces, they change the shape of the wing. This increase in speed is a result of and part of lift generation.

Bernoulli’s principle is in operation on all aircraft but it’s an approximation that assumes that air is incompressible. This is nearly true for low-speed aircraft (light planes etc.) but becomes increasingly inaccurate as speeds rise. At the speeds of modern airliners it’s useless as a way to predict anything. Bernoulli’s principle isn’t a ‘natural law’ it’s a tool for prediction of effects.

Helicopters work the same way – and they can also fly upside down but usually don’t.

Aeroengineer says: February 23, 20123:00 pm

Pittance, sorry not to be rude but I would hate for anyone reading this to be mis-informed by your quite frankly grossly inaccurate statements.

For starters, the whole idea that lift is generated by ‘Newton’s second law’ is just incorrect. So yes, air is deflected downwards by a lifting aerofoil, true enough, but, it will only be deflected through the same angle as the angle of incidence, but then there is also upwash ahead of the wing, that’s before you start on what happens behind the wing, but all streamlines of flow ahead of the aerofoil will be at the same height after the aerofoil has passed, thus no net air deflection in any direction. Considering the Coanda effect on the curved surface is just plain wrong.

The Bernoulli effect as a qualitative explanation for flight works pretty well, but yes it does break down mathematically in that it does not account for energy losses due to friction, compressibility effects or unsteady flow, but it is a reasonably accurate model for most situations. It is most generally challenged by the two concepts 1) that flat surfaces can produce lift (i.e. with zero camber) and 2) that under smokeline examination, air over the top surface overtakes air on the underside of the surface… but it’s ‘half’ right.

The theory of circulation, whereby an aerofoil sets up circulatory motion of the fluid is a mathematically correct model for the generation of flight, making use of the Kutta condition, Magnus throry and various other effects/observational laws.

As for inverted flight, look at a tailplane, they are generally symmetrical about their chord line so that they can produce lift equally in both directions of movement, which goes on to say for what you need to fly upside down.